Certain types of glasses are susceptible to colorization and reduced optical transmission (i.e., higher optical absorbance) at visible wavelengths when subjected to high-energy UV radiation. In particular, a color center around 500 nm can arise wherein the glass takes on a pink colorization or hue due to increased absorption of blue-wavelength light relative to the red wavelengths. The UV-induced colorization can occur for example when the glass is subjected to a process that includes relatively high-intensity deep ultraviolet (DUV) radiation as the main processing vehicle, or as a byproduct to different processing vehicle. For example, high-energy DUV radiation is present in substantial amounts as a byproduct in plasma cleaning processes and sputter deposition processes.
UV-induced glass colorization can be disadvantageous, especially in applications where the glass is intended for use at visible wavelengths where substantially equal transmission over the visible wavelength range is required. Examples of such use in consumer electronics include using transparent glass sheets as cover glasses for various types of displays, which can range in size from a one or a few inches (e.g., cell phones, smart phones, etc.) to several feet (e.g., large-screen televisions).